Static images are increasingly being stored in digital form, for example in computer memories. This is partly due to the increase in use of computer scanners and digital camera equipment. One of the main advantages of providing an image, e.g. a photograph, in digital form, is that it can be edited on a computer, displayed on a computer screen, or, with suitable equipment, displayed on a television screen.
Owing to the fact that such digital images (as with all static images) inherently hold a viewer's attention for a limited period of time, methods have been devised for producing a moving image from a static image. Such methods are commonly referred to as ‘rostrum camera’ techniques. A conventional rostrum camera is a film or television camera mounted vertically on a fixed or adjustable column, typically used for shooting graphics or animation—these techniques for producing moving images are of the type that can typically be obtained from such a camera. Essentially, these techniques involve different parts of the static image being displayed over time to provide an overall motion effect ‘over’ the image. For example, a perceivable panning motion from one part of the image to another might be employed. As a further example, a zooming effect might be used. The main purpose of using such rostrum camera techniques is to generate continued interest in an image by converting a static image into a moving image (or rather, a series of consecutive static images so arranged to represent motion). Rostrum camera techniques also have advantages in terms of displayable resolution. By moving over an image, detail of an image can be shown that otherwise cannot be shown on a low resolution display (without zooming-in).
Such conventional rostrum camera techniques are generally manual, in that they require a user to observe the displayed image, and manually to plot the path or order of the image parts to be displayed in a moving sequence. This can be time consuming, and requires some technical knowledge of camera equipment or digital image editing software. In order to provide a good-quality moving image, particularly for photographs of real-life scenes, some knowledge of photographic composition is also required. This is clearly disadvantageous to an average person who wishes to add some degree of interest and variation to, say, a still photograph.
Basic automation of rostrum camera techniques are provided in a few digital image editing packages, such as ‘Photo-Vista’ from MGI Software Corp. Such a package provides a virtual moving viewpoint of a static digital image by moving from one side to the other, by moving in a wave like motion, or by displaying random parts (much like a screensaver slide-show). However, no account is taken of the image content, and no photographic composition (even at a basic level) is accounted for.
In many conventional techniques, computer memory is taken-up with displaying uninteresting parts of images and of those image parts that are considered significant or interesting, only small sections may be shown with a ‘cutting-off’ effect. Also, in terms of digital examples, large amounts of time and computational resources are used.